Attachment for pneumatic riveters.



H. B. 'GRINBR. ATTACHMENT FOR PNEUMATIC RIVETERS. APPLICATION FILED JAL31, 1914.

Patented May 26, 1914 .WIINESSES a mvsum 7 AQ/2 M I A I TTORNYS- UNITED STATES PATENT OFFICE.

HARRY B. GRINEB, OF .EI-IILADELPIE-IIA PENNSYLVANIA.

ATTACHMENT FOR PNEUMATIC RIVETERS.

Specification of Letters Patent.

Patented May 26, 1914.

Application filed January 31, 19-14. Serial No. 815,629.

greater than its own length, and reciprocates several hundred times a minute and imparts a hammering blow to the working tool, rivet set or button set, a comparatively high pressure of the motive fluid is employed and the rivet set or piston is liable to be accidentally impelled from the tool cylinder and either lost by dropping to the ground or into the water, when the implement is used on bridge work, and in addition, it some-. times happens that by-standers or operators are struck by the rivet set or the piston which may be impelled from the tool cylinder with great velocity and serious injury is thereby caused. The liability. of danger from these causes has become recognized to such an extent in some States that legislation has already been passed requiring pneumatic riveting hammers to be equipped with a tool retainer of some character and the present invention relates to a novel construction of such a, pneumatic tool retainer designed to be employed in conjunction with pneumatic tools of the riveter type, wherein the piston may or may not have a length of stroke greater than its own length.

With the end in view of preventing the disadvantages of the older forms of pneumatic impact tools, my present invent-ion consists of a closure for the lower end of the bore of the barrel of a pneumatic impact tool, which serves as an abutment against which the piston can strike and be prevented from assing out at the end of the bore.

It further consists of such a closure against which a shankless rivet-set or other working-tool can abut to receive the impact of the blows from the reciprocating piston in the hammer barrel.

It further consists of other novel features of construction, all as will be hereinafter fully set forth.

The annexed drawing and the followingdescription set forth in detail, one mechanical form embodying the invention, such de-' tail construction being but one of various mechanical forms in which the principle of the invention may be used.

In said annexed drawings-Figure 1 represents an axial section of the lower portion of the barrel of a pneumatic impact-tool, illustrating the piston, impact-plug and rivet-set in side elevation. Fig. 2 represents a perspective view of the split retaining washer. Fig. 3 represents a perspective view of one form of working tool, being a countersink rivet-set.

Similar numerals of reference indicate -corresponding parts in the figures.

Referring to the drawings, the reference numeral 1 indicates the barrel of apneumatic impact tool, having the usual axial bore, 2, in which a piston, 3, is reciprocable. An annular channel or enlargement, 4:, is formed in the bore, near the lower end of the same, and the bore has an annular shoulder 5, below such channel and continues in a bore, 6, of smaller diameter than the main bore or working cylinder, and. having an annular recess or rabbet, 7 at its lowermost end. An impact-plug, 8, has a snug fit in the lower part of the bore, having an enlarged upper portion, 9, which extends from the annular channel to the shoulder, against which it bears with a shoulder, 19, and which fits in the larger-diameter portion in the bore, and a small-diameter lower portion, 10, which fits in the small-diameter portion of shoulderto the lower end of the bore. A split retaining washer, 11, fits upon the lower end of the impact plug, within the annular rabbet, and serves to'prevent the impact-plug from sliding back into the bore of the barrel, when the tool is reversed with the handle lower than the working tool. The working tool, 12, in the present instance, a-rivet-set, has a plane inner face, 13, wi h which it bears against the lower end of the barrel and the end of the impactplug, and has a wide peripheral groove, 14, which is engaged by the contracted outer end, 15, of a split, tapering clip, 16, the inner edge of which is formed into an inwardly projecting lip, 17 engaging an annular groove, 18, in the lower end of the barrel.

In practice, the shouldered impact-plug is inserted at the upper end of the bore of the barrel, the handle having been removed, and is moved to the lower end to have the shoulder of the plug rest against the shoulder in the bore of the barrel. The split retaining washer is spread and placed upon the end of the plug within the annular recess in the end of the bore, .where it clamps the end of the plug and prevents the same from sliding into the bore when the tool is tilted with the handle downward.

The fit of the plug with its stepwise reduction of diameter in the bore having a corresponding stepwise reduction of diameter, by the shoulders upon the latter and in the bore, issufiiciently snug to practically form an airtight closure for the lower end of the cylinderbore. In a tool especially made for this construction, the bores of two diameters and the annular rabbet are formed in the barrel when the latter is bored and turned, but a barrel of the pneumatic hammering tools now in general use may have its toolsocket bored to produce the shoulder and the annular recess. The blows of the reciprocating piston are through the impact-plug to the working tool or rivet-set. As the rivet-set has no shank but has a plane inner face, rivet-sets, the shanks of which have been broken in tools of the usual character, can be adapted for use in this tool by cutting the inner face plane. The impact-plug has no play in the bore of the barrel, and a part of the impact of the reciprocating piston falls upon the cylinder through the shoulders of the plug and bore and is communicated to the working tool or rivet-set, the face of which bears against the end of the barrel.

It is found from practical use of the tool that it possesses less vibration than tools in which the piston strikes directly upon the shank of a rivet-set loosely fitted in a tool-socket, and that there is no waste of air at the lower end of the barrel. The piston is retained in the bore of the barrel and cannot be shot out of the same as in the tools now in general use, whereby danger of injury from such piston is avoided. The piston cannot drop outand be lost or covered with dirt and grit, as in the tools now generally used, whereby undue wear of the piston and bore is avoided, a trouble which has obtained extensively in the old-style tools,as the operatives rarely thoroughly clean the piston if it is dropped.

The working tool and an impact-tool embodying the broad principle of closing the lower end of the bore in the barrel and dispensing with the direct impact of the piston, is disclosed in a copending application, filed by me on Dec. 16th, 1913, Serial No. 807,027.

Other modes of applying the principle of my invention may be employed for the communicated mode herein explained. Change may therefore be made as regards the mechanism thus disclosed, provided the principles of construction set forth, respectively, in the following claims are employed.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. In a pneumatic impact tool, a barrel having the lower portion of its bore of stepwise decreasing diameters, an impact-plug of corresponding stepwise decreasing diameters and fitting in said bore, and means surrounding a portion of said plug and adapted to contact with said barrel for pre venting upward displacement of such plug.

2. In a pneumatic impact tool, a barrel having the lower end of its bore of less diameter than the latter to form an upwardly facing annular shoulder, an impact-plug fitted in the bore to have its portion of less diameter fit in the bore of less diameter and extending to the end of the barrel and a portion of greater diameter to fit in the bore and form a shoulder fitting against the shoulder of the bore, and means surrounding a portion of said plug and adapted to contact with said barrel for preventing upward movement of such plug.

3. In a pneumatic impact tool, a barrel having a portion of the lower end of its bore of less diameterthan the latter to form an upwardly facing annular shoulder and having an annular rabbet in the end of such reduced portion, an impact-plug fitting in the lower portion of the bore and having a portion of reduced diameter fitting in the bore of less diameter and extending to the lower end of the barrel and a portion of greater diameter fitting in the bore and forming a downwardly facing annular shoulder fitting against the shoulder in the bore, and a split retaining washer clamping the lower end of the plug within the annular rabbet.

4. In a pneumatic impact tool, a barrel having the lower portion of its bore of stepwise decreasing diameters, an impact-plug of corresponding stepwise decreasing diameters and fitting in said bore, means for preventing upward displacement of such plug, and a working tool having a plane inner face bearing against the lower end of the barrel and of said impact-plug.

5. In a pneumatic impact tool, a barrel having the lower end of its bore of less diameter than the latter to form an upwardly facing tool having a plane imier face bearing against the lower end of the barrel and of said impact-plug.

6. In a pneumatic impact tool, a barrel having a portion of the lower end of its bore of less diameter than the latter to form an upwardly facing annular shoulder and vhaving an annular rabbet in the end of such reduced portion, an impact-plug fitting in the lower portion of the bore and having a portion of reduced diameter fitting in the bore of less diameter and extending to the lower end of the barrel and a portion of greater diameter fitting in the bore and formin a downwardly facing anngilar. shoulder fitting against the shoulder inthe bore, a split retaining washer clamping the lower end of the plug within the annular rabbet, anda working tool having a plane inner face hearing against the lower end of the barrel and of said impact-plug.

7. In a pneumatic impact tool, a barrel having the lower portion of its bore of stepwise decreasing diameters, an impact-plug of corresponding stepwise decreasing diameters and fitting in said 'bore, means for preventing upward displacement of such plug, a working tool having a plane inner face bearin against the lower end of the barrel.

and 0 said impact-plug, and means for holding such plane face of the working tool against the lower end of the barrel and of the impact-plug.

8. In a pneumatic impact tool, a barrel having the lower end of its bore of less diameter t an the latter to form an upwardly facing annular shoulder, an impact-plug fitted in the bore to have its portion of less diameter fit in the bore of less diameter and extending to the end of the barrel and a portion of greater diameter to fit in the bore and form a shoulder fitting against the shoulder of the bore, means for preventing upward movement of such plug, a working. tool having a plane inner face bearing against the lower end of the barrel and of said impact-plug, and means for. holding such plane face of the working tool against the lower end of the barrel and of the impact-plug.

9. In a pneumatic impact tool, a barrel having a portion of the lower end of its bore of less diameter than the latter to form an upwardly. facing annular shoulder and having an annular rabbet in the end of such reduced portion, an impact-plug fitting in the lower portion of the bore and having a portion of reduced diameter fitting in the bore of less diameter and extending to the lower end of the barrel and a-portion of greater diameter fitting in the bore and forming a downwardly facing annular shoulder fitting against the shoulder in the bore, a split retaining washer clamping-the lower end of the plug within the annular rabbet, a working tool having a plane inner face bearing against the lower end of the barrel and of said impact-plug, and means for holding such plane face of the working tool against the lower end of the barrel and of the impact-plug.

10. In a pneumatic impact tool, a cylinder .having the lower end of its bore closed, a

working tool having a plane inner face bearing against such closed end and means interlocking with the outer faces of said cylinder and, working tool to retain said tool in operative position.

11. In a. pneumatic impact tool, a cylinder having the lower end of its bore closed, a working tool having a plane inner face bearing against such closed end, and means for holding such plane inner face against said closed end and permitting limited relative longitudinal movement of said tool and cylinder.

12. In a pneumatic impact tool, a barrel having the lower portion of its bore of stepwise decreasing diameters, an impact-plug of corresponding stepwise decreasing diameters and fitting in said bore and a split ring engaging the forward end portion of said impact-plug and adapted to contact with said barrel to limit rearward movement of said impact-plug.

13. In a pneumatic impact tool, a barrel having the lower end of its bore of less diameter 'than the latter to form an upwardly facing annular shoulder, and an im pact-plug fitted in the bore to have'its portion of less diameter fit in the bore of less diameter and extending to the end of the barrel and a portion of greater diameter to fit in the bore and form a shoulder fitting against the shoulder of the bore.

HARRY B. GRINER.

Witnesses E. HAYWARD FAIRBANKS, C. D. MCVAY. 

